The following routes of infection are typical for embedded systems:
- An infected company intranet, if embedded systems can be accessed from it;
- Vulnerabilities that exist due to the absence of security updates;
- Employee removable data-storage devices (including those that have been used for purposes other than embedded systems maintenance);
- Hacker-owned removable data-storage devices, if the hackers have unauthorized access to ATM equipment compartments;
- Internet sites visited by company personnel during maintenance periods.
Therefore, anti-virus protection that includes a traffic control module and an access restriction module for removable data-storage devices and Internet resources is essential for embedded systems to operate normally.